Game Changer - AlphaZero's Groundbreaking Chess Strategies
This is an extract from the book Game Changer - AlphaZero's Groundbreaking Chess Strategies and the Promise of AI by Matthew Sadler and Natasha Regan, published by New In Chess.
***
This book is about an exceptional chess player, a player whose published games at the time of writing total just 10, but whose name already signifies the pinnacle of chess ability.
A powerful attacker, capable of defeating even the strongest handcrafted chess engines with brilliant sacrifices and original strategies; and a player that developed its creative style solely by playing games against itself.
That player is AlphaZero, a totally new kind of chess computer created by British artificial intelligence (AI) company DeepMind.
Through learning about AlphaZero we can harness the new insights that AI has uncovered in our wonderful game of chess and use them to build on and enhance our human knowledge and skills.
We talk to the people who created AlphaZero, and discover the struggles that brilliant people face when aiming for goals that have never before been achieved.
The authors feel extremely privileged to have worked with the creators of AlphaZero on this project.
We recognise this as a defining moment, being right at the cutting edge of fast-developing technology that will have a profound effect on all areas of human life.
Our collaboration arose following the publication of 10 AlphaZero games during the December 2017 London Chess Classic tournament.
The previous year, Matthew and Natasha had won the English Chess Federation (ECF) Book of the Year award for Chess for Life, a compilation of interviews with icons of chess, highlighting themes and core concepts of their games.
We knew we could take a similar approach to AlphaZero, offering critical insight into how the AI thinks and plays, and sharing key learnings with the wider chess-playing community.
***
Reducing the mobility of the opponent’s forces to create opportunities
In this section AlphaZero reduces the opponent’s forces to passivity using sacrificial and other techniques.
Squeezing with the pawns
Game: ‘Endgame class’
AlphaZero unexpectedly offers up an advanced rook’s pawn on the queenside – which looked to be a useful advantage for the endgame – to reduce the activity of White’s pieces.
The knight decentralises to win the pawn, the dark-squared bishop is restricted by pawn phalanxes on b6/c5 and h4/g3, and most importantly the king is rendered passive.
AlphaZero converts its edge by keeping the white king pinned to the corner and trading off Stockfish’s active pieces.
The result for Stockfish is a useless knight on f6, a rook tied to the back rank and an unstoppable passed c-pawn to contend with.
Game themes:
1. Sacrificing material to reduce the opponent’s activity [31…c5]
2. Reducing the opponent’s activity with pawn advances [31…c5, 32…g5, 33…g4, 34…g3]
3. Opponent’s passive pieces [♔g1, ♘f6]
4. Exchanging off the opponent’s active pieces to leave passive ones [51…♖xa1, 57…♗c5]
5. Lonely knight [♘f6]
Stockfish 8
AlphaZero
London 2018
8
7
6
5
4
3
2
1
a
b
c
d
e
f
g
h
Already having some experience of AlphaZero’s play, I was expecting AlphaZero to exchange off its dark-squared bishop for the knight on d4 and play the rook and opposite coloured bishops middlegame, hoping to invade the weakened central light squares and play on the weakness of the fixed a2-pawn.
That probably wasn’t a bad plan, but AlphaZero’s creative strategy took me completely by surprise.
31...c5 32.♘c2 g5
8
7
6
5
4
3
2
1
a
b
c
d
e
f
g
h
Giving away the a3-pawn, which to my eyes was one of Black’s strongest assets!
However, AlphaZero is trading this asset for a series of other dynamic plusses.
33.♘xa3 g4 34.♔g1 g3
8
7
6
5
4
3
2
1
a
b
c
d
e
f
g
h
With this manoeuvre, Black has gained space on the kingside and severely restricted the freedom of the white king and dark-squared bishop.
By sacrificing the a3-pawn, Black has gained a new potential channel for entry into the White position: the a-file.
35.♗e3 ♖a8 36.♘c4 ♖h6 37.♖b2 ♖a6
White is by no means helpless as Black’s position is extended and AlphaZero has a lot of squares to protect with limited forces.
However, AlphaZero just seems to have it all under control and will first absorb White’s current temporary activity before proceeding to push White back and reclaim all that White has gained.
38.♗c1 b5 39.♘e3 ♖a4 40.c4 40.♘d5 looked natural to me.
Playing around with the engines in this position fails to deliver anything resembling clear equality: 40...♗d8 41.♘f6+ ♗xf6 42.exf6+ ♔d8 43.f7 ♖f6 44.♖e5 ♖xf7 45.♖xc5 ♖e7 46.♖e5 ♖e4 is still problematic for White due to the weakness of the back rank: 47.♔f1 ♖7xe5 48.fxe5 ♗e6 and the white king will not escape: ...♗c4+ is coming.
40...bxc4 41.♘d5 c3 42.♘xc3 ♖c4 43.♗d2 ♖c6 44.♔f1 ♗e6 45.♖b1 ♖b4 46.♖ee1 ♗c4+
8
7
6
5
4
3
2
1
a
b
c
d
e
f
g
h
AlphaZero’s pieces advance inexorably, increasing the difference in activity between its pieces and the opponent’s pieces.
46...♗c4+ seals the white king in its box on the kingside: the bishop stops the king escaping via f1-e2 whilst the g3-pawn covers f2 and h2.
47.♔g1 ♖c8 48.♖bc1 ♗d3 49.♘d5 ♖b2 50.♗c3 ♖xa2 51.♖a1 ♖xa1
Typical AlphaZero play, exchanging off active pieces to leave the opponent with passive pieces: we will see another example on move 57.
52.♗xa1 c4 53.♘f6+ ♔d8 54.♗c3 ♖b8 55.♗d4 ♗b4 56.♖d1 ♖b5 57.♔h1 ♗c5 0-1
8
7
6
5
4
3
2
1
a
b
c
d
e
f
g
h
White’s lonely knight – established on an outpost on f6 but unable to influence the struggle to stop the c-pawn – and boxed-in king are testament to the grandeur of AlphaZero’s strategy.
The c-pawn will not be stopped!
57...♗c5 58.♗xc5 ♖xc5 59.♔g1 ♔e7 60.♔h1 c3 wins.
HISTORICAL PARALLEL
Magnus Carlsen’s Grünfeld play
This encounter between the current World Champion Magnus Carlsen when he was just 17 and the Ukrainian genius Vasily Ivanchuk has themes of AlphaZero’s games in the Grünfeld Defence, and the games in which AlphaZero built up play on the kingside while Stockfish’s queenside counterplay never got going.
The switchback 23.♕c1, through which the decisive invasion happens on the flank where Black should be strongest, reminds me of AlphaZero.
Magnus Carlsen 2690
Vasily Ivanchuk 2750
Morelia/Linares 2007 (11)
1.d4 ♘f6 2.c4 g6 3.♘c3 d5 4.cxd5 ♘xd5 5.e4 ♘xc3 6.bxc3 ♗g7 7.♗c4 c5 8.♘e2 ♘c6 9.♗e3 0-0 10.0-0 ♘a5 11.♗d3 b6 12.♖c1 cxd4 13.cxd4 e6 14.♕d2 ♗b7
8
7
6
5
4
3
2
1
a
b
c
d
e
f
g
h
A typical Grünfeld structure has arisen in which White’s strong centre is counter-balanced by Black’s queenside pawn majority.
Black’s most difficult problem is to find a good spot for his knight, which tends to hang around a bit in the early middlegame (as here on a5).
There is another less obvious challenge to Black’s position: his kingside has been weakened by the exchange of his king’s knight on move five.
15.h4
The young Carlsen plays a move that AlphaZero likes too!
White exerts pressure on the black kingside with the h-pawn.
15...♕e7
The pawn is poisoned: 15...♕xh4 16.♗g5 ♕h5 17.♘g3 ♕g4 18.♗e2.
15...♕d7 is the standard move in this position.
The queen assists the exchange of rooks on the c-file but loses sight of the kingside dark squares a little.
A high-class game continued: 16.h5 ♖fc8 17.♖fd1 ♖xc1 18.♖xc1 ♖c8 19.♖xc8+ ♕xc8 20.♗h6 ♗xh6 21.♕xh6 ♗a6 22.♕d2 ♗xd3 23.♕xd3 ♔g7 24.♕d2 f6 25.e5 ♘c6 26.exf6+ ♔xf6 27.♕h6 with a clear advantage in Kir. Georgiev-Bukavshin, Aix-les-Bains 2011.
16.h5 ♖fc8 17.e5
8
7
6
5
4
3
2
1
a
b
c
d
e
f
g
h
We saw this idea in AlphaZero’s Grünfeld games as well: the pawn on e5 reduces the activity of Black’s dark-squared bishop on g7 and fixes Black’s dark-squared weaknesses on that wing too by creating an outpost on f6 for a white bishop or knight.
17...♖xc1 18.♖xc1 ♖c8 19.♖xc8+ AlphaZero chooses the same approach in this position!
Exchanging the rooks prevents the knight on a5 from activating itself (a move like 19.♖d1 would have been met by 19...♘c4) and allows White to maintain the attacking tempo.
19...♗xc8 20.♗g5 ♕c7 21.♗f6 ♘c6 22.♕g5
8
7
6
5
4
3
2
1
a
b
c
d
e
f
g
h
A powerful move, threatening 23.♗xg7 and 24.h6+, making AlphaZero-style use of the advanced h-pawn to target the dark squares around the black king.
22...h6 23.♕c1
A fantastic switchback!
Black must defend his kingside (which he was forced to weaken with 22... h6) but this gives White a tactical opportunity to exploit the pin on the black knight on the open c-file.
The file intended for black counterplay has become White’s decisive channel of entry, as so often happens when the mobility of one side is much greater than the other.
23...g5 24.♗b5 ♗d7 25.d5 exd5 26.♘d4
Winning a piece.
26...♗xf6 27.exf6 ♕d6 28.♗xc6 ♕xf6 29.♗xd7 ♕xd4 30.g3 ♕c5 31.♕xc5 bxc5 32.♗c6 d4 33.♗b5 ♔f8 34.f4 gxf4 35.gxf4 1-0.
Restricting queen mobility
As we discuss in the chapter on ‘Defence’, Stockfish is skilled at using its queen to slow down the build-up of an opponent’s attack by harrying the opponent’s pieces and sowing confusion.
The game ‘Using a queenside file to defend the kingside’ is a fine example of this.
It was a striking theme from the games released in December 2017 that AlphaZero could render Stockfish’s queen completely passive.
Let’s see one of those games:
Game: ‘Risky rooks’
A remarkable occurrence: in the middlegame the black queen is boxed into the corner with just one legal move.
Game themes:
1. Sacrificing material to reduce the opponent’s activity [47.♖xc5]
2. Opponent’s passive pieces [♕h8]
AlphaZero
Stockfish 8
London 2017
8
7
6
5
4
3
2
1
a
b
c
d
e
f
g
h
Black has been under pressure since White sacrificed a pawn in the opening.
The strange move 45...♕h8 is the choice of my engines when analysing for six hours or more.
AlphaZero finds a magical way to make the queen wish she had not retreated to the corner.
46.♕b4 ♘c5 47.♖xc5 bxc5 48.♕h4 ♖de8 49.♖f6 ♖f8 50.♕f4
8
7
6
5
4
3
2
1
a
b
c
d
e
f
g
h
The black queen is completely imprisoned.
Black can only sit and await its fate.
50...a5 51.g4 d5 52.♗xd5 ♖d7 53.♗c4 a4 54.g5 a3 55.♕f3 ♖c7 56.♕xa3 ♕xf6 57.gxf6 ♖fc8 58.♕d3 ♖f8 59.♕d6 ♖fc8 60.a4 1-0
HISTORICAL PARALLEL
Judit Polgar’s ♕f6!
The stunning move 49.♖f6 reminded me of an idea played by Judit Polgar – one of the world’s elite players until her retirement – against the French grandmaster Laurent Fressinet.
The following position was reached after 24 exciting moves in a Najdorf Sicilian:
Judit Polgar 2656
Laurent Fressinet 2536
Istanbul ol 2000 (9)
8
7
6
5
4
3
2
1
a
b
c
d
e
f
g
h
24...♖c4
As Judit explains in volume two of her Best Games collection, she thought for 32 minutes after Black’s 24th move, which shows the difficulty of the position.
25.♕b8+ ♔g7 26.♕e5+ ♔g8
8
7
6
5
4
3
2
1
a
b
c
d
e
f
g
h
27.♕f6
A fantastic move.
The queen ties down the black king and the rook on h8 completely while preparing ♖h1-d1-d8+.
The key difference with 27.♖d1 is seen in the game after 27...♕c7.
A) 27.♖d1, which Judit wanted to play, fails to 27...♕c7 28.♕f6 ♕f4+ 29.♔b1 ♕xf6 when the queen on f6 covers d8 and stops the intermediate check 30.♖d8+;
B) 27.♖e1 was Judit’s next idea, but after much examination, she decided that 27...♖c5 would destroy the coordination of White’s pieces and take control of the e5-square: the rook cannot be taken because of mate on e1.
But then inspiration and tactical genius struck!
27...♕c7 28.♖e1 ♕c6
Why doesn’t 28...♕f4+ work?
Well in comparison to 27.♖d1, the rook is now on e1, which means that after 29.♔b1 ♕xf6 White can interpose 30.♖e8+, winning a piece after 30...♔g7 31.gxf6+ ♔xf6 32.♖xh8.
Wonderful tactical ingenuity!
The defence in the game also didn’t work.
29.♗e6 fxe6 30.♖d1 1-0
Black resigned as 30...♕e8 31.♖d8 ♕xd8 32.♕xd8+ ♔g7 33.♕f6+ ♔g8 34.♕xe6+ ♔g7 35.♕f6+ ♔g8 36.♕xa6 leads to a winning position for White, with queen and three enormous passed pawns on the queenside.
A stunning finish.
***
Comment
© chess24.com | All rights reserved
| Version: 1.1.19